Robotic end effector for holding solar cells from Schunk

Actuated with compressed air at 6 bar, a transportation cycle of 550 mm, including inspection with a camera system on the return, is carried out in a cycle time of less than 1 second. The SZG is based on the Bernoulli principle. A low-pressure at the gripping surface has the effect that wafers made of cristalline silicon, with a thickness of 110 microns, are gripped gently but with a high holding force. Special silencers at the gripper bottom side, a polyurethane friction lining and a large support face provide a stress-free and safe grip, where even shearing forces can be absorbed reliably. Integrated micro valves shorten the movement of the compressed air to allow a short response time where wafers can be blown out when they are deposited. A large area of the cell surface can be mounted at a distance of approximately 7 mm, allowing the air flow to automatically remove dust particles from the wafer. As the cell is located above the gripper, a vision system can inspect the complete wafer edge, which increases process quality and reliability. In order to control the complete process reliably with a vision sensor, the 140 by 140 mm base plate can be designed transparently. With a transmitted light, the wafer surface can also be inspected for cracks.